GRIPPING ARM FOR A ROCK DRILLING EQUIPMENT OR THE LIKE PROVIDED WITH A CARTRIDGE FOR RODS

Abstract: A gripping arm (4) for a rock drilling equipment or the like provided with a cartridge for rods. The gripping arm (4) comprises an abutment jaw (13) mounted longitudinally displaceably. A clamping jaw (12) secured to a clamping cylinder (11) forces a rod (6) against the abutment jaw when the rod is gripped. Aligning openings (13a to 13c, 11a, 11b) are bored in the body of the abutment jaw (13) and in the frame of the clamping cylinder (11). The openings (13a to 13c, 11a, 11b) corresponding to each rod diameter are aligned with each other, aligning pins (16) are inserted through the openings, and the abutment jaw is tightened immovable by bolts (15).

Description: Gripping arm for a rock drilling equipment or the like provided with a cartridge for rods The invention relates to a gripping arm for a rock drilling equipment or the like provided with a cartridge for rods, the gripping arm comprising an abutment jaw, a clamping cylinder, and a clamping jaw attached to the clamping cylinder so as to be moved by it for clamping a rod between the jaws, and the gripping arm being mounted turnably in the transverse direction of the rod with respect to the rock drilling equipment such that the gripping arm can be turned to the rod positioned at a predetermined distance from the turning axis of the gripping arm so that the abut- ment jaw and the clamping jaw will be positioned on opposite sides of the rod in the longitudinal direc¬ tion of the gripping arm. Mechanized rock drilling widely employs a cartridge technique in which drill rods or pipes used in long hole drilling are stored in various drill cartridges out of which the rods or pipes are taken one by one as the drilling proceeds or returned one by one into the cartridge when the drill rod set is broken up. Correspondingly, bolts used in rock bolting are stored in cartridges out of which they are taken one by one for the bolting process. As used in this patent application and claims, the rock drilling equipment refers both to rock drilling equipment used solely for rock drilling and to rock bolting equipment in which either drill rod or drill pipe sections or rock bolts are stored in a cartridge for later use. The rod, in turn, refers in this patent application and claims to a drill rod, drill pipe, bolt or the like, which is stored in the cartridges of the rock drilling equipment. Drill pipes, rods or bolts are handled, i.e. picked up from and inserted into the cartridge, by separate gripping arms each comprising an abutment jaw mounted fixedly to the frame and a movable clamping jaw driven by a hydraulic or pneumatic cylinder. A rod, i.e. a drill pipe, drill rod, or bolt, is picked up in the following way: the bolting equipment or the rock drill is turned close to the rod and then the pairs of jaws in the concurrently moving gripping arms are displaced in the transverse direction of the rod to its opposite sides by turning the gripping arms, and the rod is then gripped by displacing the clamping jaws by the cylinder so that the rod will remain in the gap defined between the jaws. The rod is then withdrawn from the cartridge by turning the bolting head or the rock drill and the gripping arms in the opposite direction. Another way to displace the rod is to use gripping arms which turn between the cartridge and the axis of the bolting head or the rock drill typically along a curved path, and so the gripping arm picks up a rod from the cartridge and then turns so as to displace the rod at the drilling centre or in alignment with a hole to be bolted. A drawback of the prior art technique is that bolts and drill rods/drill pipes of different thick¬ nesses require clamping jaws of different dimensions. This implies that a different gripping arm has to be manufactured for each rod size, which increases the number of required spare parts and ties up capital unreasonably. Moreover, if bolts of different thick¬ nesses are to be installed by the same equipment, or the drilling means of the equipment are to be changed, it is always necessary to change the gripping arm as well. The object of the present invention is to provide a gripping arm which can be used for rods of different thicknesses simply and easily. The gripping arm according to the invention is characterized in that the abutment jaw is mounted to the gripping arm displaceably in the longitudinal direction of the clamping cylinder such that it can be adjusted in accordance with the diameter of the rod to be used so that the stop face of the abutment jaw will be posi¬ tioned substantially in abutment with the outer surface of the rod when the gripping arm has been turned so that the jaws are positioned on opposite sides of the rod, and that the abutment jaw is arranged to be fixed in a desired position. An essential feature of the invention is that the abutment jaw associated with the gripping arm is mounted longitudinally displaceably with respect to the gripping arm, so that it can be mounted at a suitable position for each rod diameter in the longitudinal direction of the gripping arm. Another essential feature of the invention is that the abutment jaw can be locked immovable with respect to the gripping arm in each one of the desired positions. An advantage of the gripping arm according to the invention is that the jaws can always be posi- tioned suitably with respect to the rod to be dis¬ placed by varying the position of the abutment jaw with respect to the gripping arm in accordance with the thickness of the rod to be displaced. In this way the clamping jaw will always be positioned appropri- ately at the gripping stage and force the rod against the abutment jaw without that the rod bends or is exposed to any other extra strains. It is thereby easy to change the bolt diameter in the bolting equipment simply by suitably adjusting the jaw of the gripping arm. Correspondingly, when the diameter of drill rods or pipes used in long hole drilling is to be changed, the gripping arm can be easily adapted by adjusting the jaw. Another advantage of the invention is that in most cases a single gripping arm type can be used in the same type of equipment, and so a large spare part store is avoided with resulting savings in investments and other costs. The invention will be described more fully with reference to the attached drawings, in which Figures la and lb are schematic views of the operation of a gripping arm according to the invention in a rock bolting equipment; Figure 2 is a schematic view of the structure of the gripping arm according to the invention when the jaws are open; Figures 3a to 3d illustrate the structure of a preferred embodiment of the invention and its adjust¬ ment for rods of different thicknesses. Figures la and lb are schematic top views of a rock bolting equipment, showing a bolt cartridge 1, a bolting head 2, a rock drill 3, and a gripping arm 4. The bolt cartridge 1, the bolting head 2 and the rock drill 3 are known per se, and the bolting equipment itself is well-known, wherefore they will not be described more closely herein. In the situation shown in Figure la, the rock bolting equipment is in a rest position, whereby all the components are shown apart from each other. In Figure lb, the unit formed of the bolting head 2 and the rock drill 3 has been turned about an axis 5, to the left in the figure, so that the bolting head is positioned at a bolt 6 contained in the cartridge 1, and the gripping arm 4 has been turned about an axis 7 towards the bolt 6 so that the jaws of the gripping arm 4, which will be described more fully below with reference to Figure 2, are positioned on opposite sides of the bolt 6. In this situation the jaws are clamped around the bolt 6. When the unit formed of the bolting head 2 and the rock drill 3 is turned to the right in the figure, the bolt 6 gripped by the gripping arm 4 follows and will be positioned on the axis of rotation of the bolting head 2. The structure and operation of the bolting equipment as such are well-known and therefore will not be described more fully herein. Figures 2 shows the gripping arm 4 in more detail. The gripping arm 4 is arranged to be turned by the hexagonal shaft 7, as also shown in Figures la and lb. The gripping arm 4 is mounted longitudinally slideably with respect to the shaft 7 and mounted in bearings turnably with respect to a stand 8. As shown in Figures la and lb, the stand 8 in turn is mounted slideably along an I-track 9, and it can be mounted immovable with respect to the I-track 9 by mounting bolts 10. The gripping arm 4 is formed by a clamping cylinder 11 to which a clamping jaw 12 is attached. It further comprises an abutment jaw 13 attached to the frame of the clamping cylinder 11 and having a body portion extending longitudinally of the gripping arm 4 so as to secure it to the gripping arm and, especially in the case shown in the figure, to the frame of the clamping cylinder 11. The abutment jaw 13 is secured to the frame of the clamping cylinder 11 by bolts 15 extending through elongated openings 14 formed in the body portion of the abutment jaw in order that the abutment jaw 13 could be displaced longitudinally of the clamping cylinder 11 to a suitable position. The aim is to mount the abutment jaw 13 so with respect to the rod 6 that when the gripping arm 4 is turned to the gripping position, the abutment jaw 13 will be positioned substantially in abutment with the surface of the bolt 6. The length of travel of the clamping cylinder 11 is thus such that when the abutment jaw 13 is in its extreme position and the clamping cylinder 11 is in its most retracted position, the thickest desired bolt 6 can be inserted between the jaws 12, 13. Correspondingly, when the abutment jaw is in a position closest to the clamping cylinder 11, the thinnest desired bolt 6 will remain clamped between the jaws 12, 13 when the clamping cylinder 11 forces the clamping jaw 12 towards the abutment jaw 13. At the gripping stage, when the rod 6 is in a position shown in Figure 2, the clamping jaw 12 is displaced onward by the clamping cylinder 11 so that the rod 6 will be supported by the edges 12a of a recess formed centrally in the jaw 12, and will thus stay in position during the displacing stage. Correspondingly, when the rod 6 has been displaced to the drilling axis or to a hole to be bolted, the clamping jaw 12 is retracted by the clamping cylinder 11 so that the gripping arm can be turned aside so that it will not hamper the movement of the rock drill or the bolting head. Figures 3a to 3d show a preferred embodiment of the gripping arm according to the invention, in which the position of the abutment jaw 13 is arranged to be easily adjustable in accordance with certain standard rod diameters. As appears from Figure 3a, the body portion of the abutment jaw 13 is provided with a number of openings 13a to 13c which in this specific case form groups of four openings at a predetermined distance from each other. Correspondingly, the frame of the clamping cylinder is provided with openings 11a and lib positioned similarly in groups of four openings at suitable distances so that when the abutment jaw 13 is in a certain longitudinal position with respect to the clamping cylinder 11, certain openings in the body of the abutment jaw 13 and certain openings in the frame of the clamping cylinder 11 will be in alignment. As appears from Figure 3b, which is a sectional view along a line A-A indicated in Figure 3a, the openings 13a of the body of the abutment jaw 13 and the openings 11a of the frame of the clamping cylinder 11 are in alignment in this specific case, and so its has been possible to insert aligning pins 16 through the openings. The abutment jaw 13 is thereby in a pre¬ determined position with respect to the clamping cylinder 11 and hence with respect to the gripping arm 4, and this position is arranged to suit a bolt 6 having a predetermined diameter. In this case, Figure 3a shows a situation in which the rod 6 has the smallest possible diameter for which the gripping arm is designed. Figure 3c in turn shows a situation in which the abutment jaw 13 has been displaced onward in the longitudinal direction of the clamping cylinder 11, that is, upward in Figure 3c, and so the openings 13b in the body of the abutment jaw 13 and the openings lib in the frame of the clamping cylinder 11 are in alignment, and it has been possible to insert aligning pins 16 through both openings. The abutment jaw 13 is thereby in a second predetermined position with respect to the clamping cylinder 11, and it will stay accurately in position when another rod 6 having a diameter greater than that of the rod shown in Figure 3a is used. In a situation shown in Figure 3d, when a still larger rod is used, the openings 13c of the body of the abutment jaw 13 and the openings 11a of the frame of the clamping cylinder 11 are in alignment, and aligning pins 16 are inserted in these openings. The abutment jaw 13 is now in its most extended posi¬ tion in the longitudinal direction of the clamping cylinder 11, and the gripping arm is capable of gripping a rod 6 of the greatest diameter for which the gripping arm is designed. The solution shown in Figures 3a to 3d is a preferred embodiment of the invention, in which both the longitudinal support and the transverse support of the abutment jaw 13 are reliably accomplished by pairs of openings and aligning pins. Accordingly, the rigidity and immobility of the abutment jaw 13 with respect to the clamping cylinder 11 are maximized, as the aligning pins 16 in the openings prevent the abutment jaw 13 from turning in the transverse direc¬ tion of the clamping cylinder 11 and the bolts 15 tighten it firmly in place. The equipment can thus be designed for rods of predetermined constant diameters, and the openings 13a to 13c and 11a to lib can be bored accordingly. The invention has been described in the text above and shown in the drawings only by way of example, and it is not in any way limited to the example. The shape of the abutment jaw may be different, and the gripping arm may comprises two abutment jaws 13 positioned on the opposite sides of the clamping cylinder. Further, the longitudinal position of the abutment jaw may be arranged to be adjusted by utilizing other ways of locking, such as aligning means of different kinds, e.g. stops.

Claims: Claims : 1. Gripping arm (4) for a rock drilling equip¬ ment or the like provided with a cartridge (1 ) for rods, the gripping arm (4) comprising an abutment jaw (13), a clamping cylinder (11), and a clamping jaw (12) attached to the clamping cylinder so as to be moved by it for clamping a rod (6) between the jaws, and the gripping arm (4) being mounted turnably in the transverse direction of the rod ( 6) with respect to the rock drilling equipment such that the gripping arm (4) can be turned to the rod (6) positioned at a pre¬ determined distance from the turning axis (7) of the gripping arm so that the abutment jaw ( 13) and the clamping jaw (12) will be positioned on opposite sides of the rod (6) in the longitudinal direction of the gripping arm (4), c h a r a c t e r i z e d in that the abutment jaw (13) is mounted to the gripping arm (4) displaceably in the longitudinal direction of the clamping cylinder (11) such that it can be adjusted in accordance with the diameter of the rod (6) to be used so that the stop face of the abutment jaw (13) will be positioned substantially in abutment with the outer surface of the rod ( 6) when the gripping arm (4) has been turned so that the jaws (12, 13) are positioned on opposite sides of the rod (6) , and that the abut¬ ment jaw (13) is arranged to be fixed in a desired position. 2. Gripping arm according to claim 1, c h a r- a c t e r i z e d in that the abutment jaw (13) comprises a body portion extending in the longitudinal direction of the gripping arm (4), and that the abut¬ ment jaw (13) is arranged to be fastened to the gripping arm (4) through openings formed in the body portion of the abutment jaw (13). 3. Gripping arm according to claim 2, c h a r¬ a c t e r i z e d in that the body portion of the abutment jaw (13) comprises two elongated holes (14) extending in its longitudinal direction, and that the abutment jaw (13) is fastened to the frame of the clamping cylinder (11) by bolts (15) extending through the holes (14) so that when the abutment jaw (13) is in a desired position, it can be tightened by the bolts (15) immovably with respect to the frame of the clamping cylinder (11). 4. Gripping arm according to claim 2 or 3, c h a r a c t e r i z e d in that the body portion of the abutment jaw (13) and the frame of the clamping cylinder (11) are provided with counterparts for each rod (6) to be used so that when certain counterparts are aligned with each other, the abutment jaw (13) will be in a suitable position for a rod (6) of a pre¬ determined diameter. 5. Gripping arm according to claim 4, c h a r- a c t e r i z e d in that the counterparts are openings (11a, lib, 13a to 13c) bored in the body portion of the abutment jaw (13) and in the frame of the clamping cylinder (11). 6. Gripping arm according to claim 5, c h a r- a c t e r i z e d in that the counterparts comprise aligning pins (16) to be inserted into the openings provided for a desired rod diameter for locking the abutment jaw (13) immovable. 7. Gripping arm according to claim 6, c h a r- a c t e r i z e d in that at least two pairs of openings are provided both in the body portion of the abutment jaw (13) and in the frame of the clamping cylinder (11) for each rod diameter.

Inventors: LAUNIEMI MARKKU, TIENARI OSSI, LAUNIEMI, MARKKU, TIENARI, OSSI
Applicants: LAUNIEMI MARKKU, TAMROCK OY, TIENARI OSSI, LAUNIEMI, MARKKU, TIENARI, OSSI
Application year: 1994
Main classification: E21B19
IPC codes: E21B19